Intrinsic Faraday spectra of ferromagnetic rutile Ti1-xCoxO2-δ

We have investigated the Faraday spectra of ferromagnetic rutile Ti1-xCoxO2-delta films grown on Al2O3 (0001). The Faraday spectra strongly depended on the film thickness, revealing the significant effect of the multiple reflections of light. The intrinsic Faraday spectra of rutile Ti1-xCoxO2-delta were corrected for this multiple reflection effect on the basis of an optical model and compared with the absorption spectra in detail. The quantitatively good correspondence between intrinsic Faraday ellipticity and optical band edge strongly suggests that rutile Ti1-xCoxO2-delta is an intrinsic ferromagnetic semiconductor. The exchange parameters, N-0 alpha and N-0 beta, were estimated as the order of similar to 0.1 eV. (c) 2006 American Institute of Physics.